JP6863109B2 - Self-adhesive silicone gel composition and its cured product - Google Patents

Description

The present invention relates to a silicone gel composition that gives a cured product having excellent self-adhesiveness, and particularly self that gives a cured product having good adhesiveness to a base material such as a metal such as copper or aluminum or an inorganic substance such as ceramic. The present invention relates to an adhesive silicone gel composition and a self-adhesive silicone gel comprising a cured product thereof.

The silicone gel composition contains an organohydrogenpolysiloxane having a hydrogen atom (that is, a SiH group) bonded to a silicon atom, an organopolysiloxane having an alkenyl group such as a vinyl group bonded to a silicon atom, and a platinum-based catalyst. , It is prepared as an addition reaction curing type organopolysiloxane composition which obtains a cured product by an addition reaction of a hydrogen atom bonded to a silicon atom to an alkenyl group. The silicone gel cured product cured by heating this silicone gel composition is excellent in heat resistance, weather resistance, oil resistance, cold resistance, electrical insulation, etc., and has a low elastic modulus and low stress, so that it can be used as an in-vehicle electronic component. It is used to protect electronic parts such as parts and consumer electronic parts. The low elastic modulus and low stress that are characteristic of the cured silicone gel are not found in other elastomer products. Further, in recent years, due to the demand for high reliability of in-vehicle electronic parts and consumer electronic parts, high adhesiveness to a base material is required for a silicone gel material used for sealing.

Since such demands are increasing, various adhesiveness improving techniques have been studied in recent years. Among them, Japanese Patent Application Laid-Open No. 07-098902, Japanese Patent No. 5025917, Japanese Patent No. 5179302, Japanese Patent No. 5587148, Japanese Patent No. 5602385, Japanese Patent No. 5631964, Japanese Patent Application Laid-Open No. 2002-338833 (Patent). Documents 1 to 7) have an adhesive component that exhibits high adhesiveness, that is, a hydrolyzable group such as a methoxy group or an ethoxy group and a functional group such as an epoxy group, an isocyanate group, or an isocyanul group in the molecule. Improvement of adhesiveness is achieved by using the silane coupling agent. However, even if the above-mentioned silane coupling agent is used, it is difficult to universally adhere to any substrate. Further, depending on the silane coupling agent used, the catalytic ability of the platinum catalyst used as the curing catalyst is lowered, so that there is a problem that the flexibility changes with time or the platinum catalyst becomes uncured. Further, Japanese Patent Publication No. 04-078655, Japanese Patent Publication No. 05-0676773, and Japanese Patent No. 2741460 (Patent Documents 8 to 10) introduce a technique for improving adhesiveness by adding an organic peroxide. This also has a problem that oxygen generated as a by-product reduces the adhesiveness with the base material and causes peeling.

Further, in JP-A-2000-309711, JP-A-2005-350582, and Patent No. 4960620 (Patent Documents 11 to 13), the structure of the organopolysiloxane used, the structure of the hydrosilyl group (SiH group), and the like are described. A technology to improve the adhesiveness by changing it has been introduced, but this method does improve the adhesion to the base material, but it has not reached the point of adhesion, so the adhesiveness decreases with long-term use. I was having a problem.

Special Fair 07-098902 Japanese Patent No. 5025917 Japanese Patent No. 5179302 Japanese Patent No. 5587148 Japanese Patent No. 5602385 Japanese Patent No. 563 1964 JP-A-2002-338833 Special Fair 04-078655 Gazette Special Fair 05-067673 Gazette Japanese Patent No. 2741460 Japanese Unexamined Patent Publication No. 2000-309711 Japanese Unexamined Patent Publication No. 2005-350582 Japanese Patent No. 4960620

The present invention has been made to solve such a problem, and is based on a metal such as copper and aluminum existing in an electronic substrate and an inorganic substance such as ceramic while maintaining the characteristics of a conventional sealing material. An object of the present invention is to provide a self-adhesive silicone gel composition that gives a cured product having good adhesiveness to a material, and a self-adhesive silicone gel composed of the cured product.

As a result of diligent studies to achieve the above object, the present inventor has added an addition reaction-curable silicone gel composition to an alkoxysilyl group-containing ketensilyl acetal represented by the following general formula (3) or (4). By adding one or more of the type compounds and / or a specific amount of a partially hydrolyzed condensate thereof, the adhesiveness is improved to a base material such as a metal such as copper or aluminum or an inorganic substance such as ceramic. We have found that a self-adhesive silicone gel composition that gives a cured silicone gel can be obtained, and have completed the present invention.
(R ³ O) ₂ Si (R ⁴ ) OC (OR ⁵ ) = CHCH ₃ (3)
(R ³ O) ₃ SiOC (OR ⁵ ) = CHCH ₃ (4)
(In the formula, R ³ and R ⁴ are alkyl groups having 1 to 4 carbon atoms, R ⁵ is an alkyl group having 1 to 12 carbon atoms, and even if R ³ , R ⁴ and R ⁵ are the same as each other. It may be a heterogeneous group.)

Therefore, the present invention provides a self-adhesive silicone gel comprising the following self-adhesive silicone gel composition and a cured product thereof.
[1]
(A) The following average composition formula (1)
R _a R ¹ _b SiO _{(4-ab) / 2} (1)
(In the formula, R is an alkenyl group independently, R ¹ is an unsubstituted or substituted monovalent hydrocarbon group independently containing no aliphatic unsaturated bond, and a is a positive of 0.0001 to 0.2. It is a number, b is a positive number of 1.7 to 2.2, where a + b is 1.9 to 2.4.)
Organopolysiloxane having at least one alkenyl group bonded to a silicon atom in one molecule on average, represented by: 100 parts by mass,
(B) The following average composition formula (2)
R ² _c H _d SiO _{(4-cd) / 2} (2)
(In the formula, R ² is an unsubstituted or substituted monovalent hydrocarbon group independently containing no aliphatic unsaturated bond, c is a positive number of 0.7 to 2.2, and d is 0.001. It is a positive number of ~ 1.0, where c + d is 0.8 ~ 3.0.)
Organohydrogenpolysiloxane having at least two hydrogen atoms bonded to silicon atoms in one molecule represented by: Hydrogen atom bonded to silicon atom in component (B) per alkenyl group in the entire composition Amount of 0.01 to 3 pieces,
(C) Platinum-based catalyst: an effective amount, and (D) one or more of the alkoxysilyl group-containing ketenylsilyl acetal type compounds represented by the following general formula (3) or (4), and / or the alkoxysilyl. Alkoxysilyl group of group-containing ketensilyl acetal type compound Ketensilyl acetal type compound having residual alkoxysilyl group formed by partially hydrolyzing and condensing : 0.01 to 10 parts by mass (R ³ O) ₂ Si ( R ⁴ ) OC (OR ⁵ ) = CHCH ₃ (3)
(R ³ O) ₃ SiOC (OR ⁵ ) = CHCH ₃ (4)
(In the formula, R ³ and R ⁴ are alkyl groups having 1 to 4 carbon atoms, R ⁵ is an alkyl group having 1 to 12 carbon atoms, and even if R ³ , R ⁴ and R ⁵ are the same as each other. It may be a heterogeneous group.)
A self-adhesive silicone gel composition containing.
[ 2 ]
A self-adhesive silicone gel comprising a cured product of the self-adhesive silicone gel composition according to [1].

The self-adhesive silicone gel composition of the present invention provides a cured silicone gel having good adhesiveness to a substrate such as a metal or an inorganic substance.

The self-adhesive silicone gel composition of the present invention contains the following components (A) to (D) as essential components. In the present invention, the cured silicone gel (self-adhesive silicone gel composed of a cured product of the self-adhesive silicone gel composition) is a cured product containing organopolysiloxane as a main component and having a low crosslink density. Consistency due to JIS K2220 (1/4 cone) (that is, connect penetration. The 1/4 cone specified in JIS K2220 has a tip needle (hardness is 45 to 50 of Rockwell C scale) at the tip of the cone body. Since the structure is equipped with a hardened steel tip needle), in the present invention, the consistency is also referred to as needle penetration, and the same applies hereinafter) of 10 to 100. This corresponds to a rubber hardness measurement by JIS K6253 that has a measured value (rubber hardness value) of 0, which is so low in hardness (that is, soft) and low elasticity that it does not show an effective rubber hardness value. In the above, it is different from the so-called silicone rubber cured product (rubber-like elastic body).

Hereinafter, each component will be described in detail. In this specification, the viscosity is a value at 25 ° C.

[(A) Organopolysiloxane]
The component (A) of the present invention is the main agent (base polymer) of the self-adhesive silicone gel composition. The component (A) is obtained by averaging alkenyl groups bonded to silicon atoms in one molecule (referred to as "silicon atom-bonded alkenyl groups" in the present specification) represented by the following average composition formula (1). It is an organopolysiloxane having at least one.
R _a R ¹ _b SiO _{(4-ab) / 2} (1)
(In the formula, R is an alkenyl group independently, R ¹ is an unsubstituted or substituted monovalent hydrocarbon group independently containing no aliphatic unsaturated bond, and a is a positive of 0.0001 to 0.2. It is a number, b is a positive number of 1.7 to 2.2, where a + b is 1.9 to 2.4.)

In the above formula (1), R is independently an alkenyl group usually having 2 to 6 carbon atoms, preferably 2 to 4, more preferably 2 or 3. Specific examples thereof include a vinyl group, an allyl group, a propenyl group, an isopropenyl group, a butenyl group, an isobutenyl group and the like, and a vinyl group is preferable. R ¹ is an unsubstituted or substituted monovalent hydrocarbon group independently containing no aliphatic unsaturated bond, and the number of carbon atoms thereof is usually 1 to 10, preferably 1 to 6. Specific examples thereof include an alkyl group such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a hexyl group, a cyclohexyl group, an octyl group and a decyl group; a phenyl group. , Aryl groups such as trill groups; Aralkyl groups such as benzyl groups and phenylethyl groups; Chloromethyl groups in which some or all of the hydrogen atoms of these groups are replaced with halogen atoms such as chlorine, bromine and fluorine, 3, Examples thereof include a 3,3-trifluoropropyl group. Of these, a methyl group, a phenyl group or a 3,3,3-trifluoropropyl group is preferable because it is easy to synthesize.

Further, a needs to be a positive number of 0.0001 to 0.2, and is preferably a positive number of 0.0005 to 0.1. b needs to be a positive number of 1.7 to 2.2, preferably a positive number of 1.9 to 2.02. However, a + b needs to satisfy the range of 1.9 to 2.4, preferably the range of 1.95 to 2.05.

The component (A) needs to have at least one silicon atom-bonded alkenyl group in one molecule on average as the whole component (A), preferably 2 to 50, more preferably 2 to 10. I have one. The values of a and b may be selected so as to satisfy the condition of the silicon atom-bonded alkenyl group.

（式中、Ｒ⁶は独立に脂肪族不飽和結合を含まない非置換又は置換の１価炭化水素基であり、Ｒ⁷は独立に脂肪族不飽和結合を含まない非置換もしくは置換の１価炭化水素基又はアルケニル基であり、但し少なくとも１個、好ましくは２〜５０個、より好ましくは２〜１０個のＲ⁷はアルケニル基であり、分子鎖両末端のＲ⁷のいずれかがアルケニル基である場合には、ｋは４０〜１，２００の整数であり、ｍは０〜５０の整数であり、ｎは０〜５０の整数であり、分子鎖両末端のＲ⁷のいずれもがアルケニル基でない場合には、ｋは４０〜１，２００の整数であり、ｍは１〜５０の整数であり、ｎは０〜５０の整数であり、但しｍ＋ｎは１以上である。）
で表されるオルガノポリシロキサン、即ち主鎖が基本的にジオルガノシロキサン単位の繰り返しからなり、分子鎖両末端がトリオルガノシロキシ基で封鎖された直鎖状のジオルガノポリシロキサンであることが好ましい。 The molecular structure of the organopolysiloxane of component (A) is not particularly limited, be linear, for example, RSiO _3/2 units, R ¹ SiO _3/2 units (R, R ¹ are as defined above) , SiO ₂ units, etc. may be included in a branched chain, but the following general formula (1a):

(In the formula, R ⁶ is an unsubstituted or substituted monovalent hydrocarbon group ^{independently containing no aliphatic unsaturated bond, and R 7} is an unsubstituted or substituted monovalent group independently containing no aliphatic unsaturated bond. is a hydrocarbon group or alkenyl group, provided that at least one, preferably 2 to 50, more preferably 2 to 10 R ⁷ is an alkenyl group, the molecular chain or an alkenyl group R ⁷ at both ends In the case of, k is an integer of 40 to 1,200, m is an integer of 0 to 50, n is an integer of 0 to 50, and ^{all of R 7} at both ends of the molecular chain are alkenyl. If not a group, k is an integer of 40 to 1,200, m is an integer of 1 to 50, n is an integer of 0 to 50, where m + n is 1 or more.)
It is preferable that the organopolysiloxane represented by is a linear diorganopolysiloxane in which the main chain basically consists of repeating diorganosiloxane units and both ends of the molecular chain are sealed with a triorganosyloxy group. ..

In the above formula (1a), the ^{unsubstituted or substituted monovalent hydrocarbon group not containing the aliphatic unsaturated bond represented by R 6} usually has 1 to 10 carbon atoms, preferably 1 to 6 carbon atoms. .. Specific examples thereof include those illustrated in ^{R 1.} Of these, a methyl group, a phenyl group or a 3,3,3-trifluoropropyl group is preferable because it is easy to synthesize.

Among the groups represented by R ⁷ , the unsubstituted or substituted monovalent hydrocarbon group containing no aliphatic unsaturated bond usually has 1 to 10 carbon atoms, preferably 1 to 6 carbon atoms. Specific examples thereof include those illustrated in ^{R 1.} Of these, a methyl group, a phenyl group or a 3,3,3-trifluoropropyl group is preferable because it is easy to synthesize. Among the groups represented by R ⁷ , the alkenyl group usually has 2 to 6 carbon atoms, preferably 2 to 4, and more preferably 2 or 3. Specific examples thereof include a vinyl group, an allyl group, a propenyl group, an isopropenyl group, a butenyl group, an isobutenyl group and the like, and a vinyl group is preferable.

In the above formula (1a), when ^{any of R 7} at both ends of the molecular chain is an alkenyl group, k is an integer of 40 to 1,200, m is an integer of 0 to 50, and n is an integer of 0 to 50. It is an integer of 0 to 50, preferably k is an integer of 100 to 1,000, m is an integer of 0 to 40, and n is 0. ^{When neither of R 7} at both ends of the molecular chain is an alkenyl group, k is an integer of 40 to 1,200, m is an integer of 1 to 50, and n is an integer of 0 to 50. Yes, but m + n is 1 or more, preferably k is an integer of 100 to 1,000, m is an integer of 2 to 40, and n is 0.

Examples of the organopolysiloxane represented by the above formula (1a) include both-terminal dimethylvinylsiloxy group-blocking dimethylpolysiloxane, both-terminal dimethylvinylsiloxy group-blocking dimethylsiloxane / methylvinylsiloxane copolymer, and both-terminal dimethylvinylsiloxy. Base-blocking dimethylsiloxane / diphenylsiloxane copolymer, both-terminal dimethylvinylsiloxy Group-blocking dimethylsiloxane / methylvinylsiloxane / diphenylsiloxane copolymer, both-terminal dimethylvinylsiloxy group-blocking methyltrifluoropropylpolysiloxane, both-terminal dimethylvinylsiloxy Base-blocking dimethylsiloxane / methyltrifluoropropylsiloxane copolymer, both-terminal dimethylvinylsiloxy group-blocking dimethylsiloxane / methyltrifluoropropylsiloxane / methylvinylsiloxane copolymer, both-terminal trimethylsiloxy group-blocking dimethylsiloxane / vinylmethylsiloxane Polymer, both-terminal trimethylsiloxy group-blocking dimethylsiloxane / vinylmethylsiloxane / diphenylsiloxane copolymer, both-terminal trimethylsiloxy group-blocking vinylmethylsiloxane / methyltrifluoropropylsiloxane copolymer, terminal trimethylsiloxy group / dimethylvinylsiloxy group Blocked dimethylpolysiloxane, terminal trimethylsiloxy group / dimethylvinylsiloxy group closed dimethylsiloxane / methylvinylsiloxane copolymer, terminal trimethylsiloxy group / dimethylvinylsiloxy group sealed dimethylsiloxane / diphenylsiloxane copolymer, terminal trimethylsiloxy group / dimethyl Vinylsiloxy group-blocking dimethylsiloxane / diphenylsiloxane / methylvinylsiloxane copolymer, terminal trimethylsiloxy group / dimethylvinylsiloxy group-blocking methyltrifluoropropylpolysiloxane, terminal trimethylsiloxy group / dimethylvinylsiloxy group-blocking dimethylsiloxane / methyltrifluoro Propylsiloxane copolymer, terminal trimethylsiloxy group / dimethylvinylsiloxy group blockage dimethylsiloxane / methyltrifluoropropylsiloxane / methylvinylsiloxane copolymer, both-terminal methyldivinylsiloxy group blockage dimethylpolysiloxane, both-terminal methyldivinylsiloxy group blockade Didimethylsiloxane / methylvinylsiloxane copolymer, both-terminal methyldivinylsiloxy group-blocking dimethylsiloxane / diphenylsiloxane copolymer, both-terminal meth Rudivinylsiloxy group-blocked dimethylsiloxane / methylvinylsiloxane / diphenylsiloxane copolymer, both-terminal methyldivinylsiloxy group-blocked methyltrifluoropropylpolysiloxane, both-terminal methyldivinylsiloxy group-blocked dimethylsiloxane / methyltrifluoropropylsiloxane copolymer , Both-terminal methyldivinylsiloxy group-blocking dimethylsiloxane / methyltrifluoropropylsiloxane / methylvinylsiloxane copolymer, both-terminal trivinylsiloxy group-blocking dimethylpolysiloxane, both-terminal trivinylsiloxy group-blocking dimethylsiloxane / methylvinylsiloxane co-weight Combined, both-terminal trivinylsiloxy group-blocked dimethylsiloxane / diphenylsiloxane copolymer, both-terminal trivinylsiloxy group-blocked dimethylsiloxane / methylvinylsiloxane / diphenylsiloxane copolymer, both-terminal trivinylsiloxy group-blocked methyltrifluoropropylpoly Examples thereof include siloxane, a double-ended trivinylsiloxy group-blocked dimethylsiloxane / methyltrifluoropropylsiloxane copolymer, and a double-ended trivinylsiloxy group-blocked dimethylsiloxane / methyltrifluoropropylsiloxane / methylvinylsiloxane copolymer.

The viscosity of the organopolysiloxane of the component (A) is not particularly limited, but the viscosity at 25 ° C. is 50 to 100,000 mPa from the viewpoint of good handling workability of the composition, strength of the obtained cured product, and fluidity. -S is preferable, and 100 to 10,000 mPa · s is more preferable. In this viscosity range, the degree of polymerization (or the number of silicon atoms in the molecule) of the organopolysiloxane of the component (A) is usually 30 to 1,500, preferably 50 to 1,000, and more preferably 100 to 100. It corresponds to about 600. In the present invention, the viscosity can be measured with a rotational viscometer (for example, BL type, BH type, BS type, cone plate type, rheometer, etc.) (hereinafter, the same applies). Further, the degree of polymerization (or molecular weight) can be measured as, for example, a polystyrene-equivalent number average degree of polymerization (or number average molecular weight) in gel permeation chromatography (GPC) analysis using toluene or the like as a developing solvent (hereinafter,). the same).

The organopolysiloxane of the component (A) can be used alone as long as it satisfies the condition that the component (A) as a whole has at least one silicon atom-bonded alkenyl group in one molecule on average. The above may be used in combination. For example, in the present invention, an organopolysiloxane having two alkenyl groups bonded to silicon atoms at both ends of a molecule, particularly at both ends of the molecular chain, and an organopolysiloxane bonded to a silicon atom in one molecule, particularly at one end of the molecular chain. Organopolysiloxane having one alkenyl group or organopolysiloxane having less than one (for example, organopolysiloxane having the same average degree of polymerization and degree of polymerization distribution and having one alkenyl group bonded to a silicon atom at one end of a molecular chain And a uniform mixture of organopolysiloxane containing no alkenyl group in one molecule, etc.) are mixed and used at a mass ratio of about 100: 0 to 40:60, particularly about 100: 0 to 60:40. However, it is preferable because the curable property of the composition is good and a flexible (high degree of needle insertion) silicone gel cured product can be stably obtained.

[(B) Organohydrogenpolysiloxane]
Next, the component (B) of the present invention reacts with the component (A) and acts as a cross-linking agent (curing agent). The component (B) has the following average composition formula (2).
R ² _c H _d SiO _{(4-cd) / 2} (2)
(In the formula, R ² is an unsubstituted or substituted monovalent hydrocarbon group independently containing no aliphatic unsaturated bond, c is a positive number of 0.7 to 2.2, and d is 0.001. It is a positive number of ~ 1.0, where c + d is 0.8 ~ 3.0.)
It is an organohydrogenpolysiloxane having at least two hydrogen atoms bonded to a silicon atom (referred to as “silicon atom-bonded hydrogen atom” in the present specification) in one molecule represented by. The number of silicon atom-bonded hydrogen atoms (that is, the hydrosilyl group represented by SiH) contained in one molecule of this organohydrogenpolysiloxane is preferably 3 to 500, more preferably 5 to 100, and particularly preferably 10 to 10. There are 80 pieces. The SiH group may be bonded to a silicon atom at the end of the molecular chain, or may be bonded to a silicon atom at the non-terminal of the molecular chain (in the middle of the molecular chain), or both of them.

In the above formula (2), R ² is an unsubstituted or substituted monovalent hydrocarbon group independently containing no aliphatic unsaturated bond, and the number of carbon atoms thereof is usually 1 to 10, preferably 1 to 6. is there. Specific examples thereof include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, cyclohexyl group, octyl group, nonyl group and decyl group. Alkyl groups such as phenyl group, trill group, xylyl group, naphthyl group and other aryl groups; benzyl group, phenylethyl group, phenylpropyl group and other aralkyl groups; some or all of the hydrogen atoms of these groups are chlorine. , 3,3,3-trifluoropropyl group substituted with halogen atoms such as bromine and fluorine. Of these, an alkyl group, an aryl group and a 3,3,3-trifluoropropyl group are preferable, and a methyl group, a phenyl group and a 3,3,3-trifluoropropyl group are more preferable.

Further, c is a positive number of 0.7 to 2.2, and preferably a positive number of 1.0 to 2.1. d is a positive number of 0.001 to 1.0, preferably a positive number of 0.005 to 0.5, and more preferably a positive number of 0.01 to 0.1. Further, c + d is 0.8 to 3.0, preferably 1.0 to 2.5, and more preferably 1.5 to 2.2.

The molecular structure of the organohydrogenpolysiloxane of the component (B) is not particularly limited, and may be any of a linear, cyclic, branched chain, and three-dimensional network (resin-like) structure, and may be contained in one molecule. The number of silicon atoms (that is, the degree of polymerization) is usually 10 to 1,000, but the handling workability of the composition and the characteristics of the obtained cured product (low elastic modulus, low stress) are good. Therefore, the number is preferably 20 to 500, more preferably 20 to 100.

Examples of the organohydrogenpolysiloxane represented by the above formula (2) include 1,1,3,3-tetramethyldisiloxane, 1,3,5,7-tetramethylcyclotetrasiloxane, and methylhydrogensiloxane. Cyclic polymer, tris (dimethylhydrogensiloxy) methylsilane, tris (dimethylhydrogensiloxy) phenylsilane, methylhydrogencyclopolysiloxane, methylhydrogensiloxane / dimethylsiloxane cyclic copolymer, both-terminal dimethylhydrogensiloxy group blockade Methylhydrogenpolysiloxane, both-terminal dimethylhydrogensiloxy group-blocked methylhydrogensiloxane / dimethylsiloxane copolymer, both-terminal dimethylhydrogensiloxy group-blocked methylhydrogensiloxane / diphenylsiloxane copolymer, both-terminal dimethylhydrogensiloxy Base-blocked methylhydrogensiloxane / dimethylsiloxane / diphenylsiloxane copolymer, double-ended trimethylsiloxy group-blocked methylhydrogenpolysiloxane, double-ended trimethylsiloxy group-blocked dimethylsiloxane / methylhydrogensiloxane copolymer, double-ended trimethylsiloxy group Examples thereof include a closed methylhydrogensiloxane / diphenylsiloxane copolymer and a double-ended trimethylsiloxy group-blocked methylhydrogensiloxane / diphenylsiloxane / dimethylsiloxane copolymer.

The organohydrogenpolysiloxane of the component (B) may be used alone or in combination of two or more. In the present invention, an organohydrogenpolysiloxane having 2 or more hydrogen atoms bonded to silicon atoms in the middle of the molecular chain (side chain), particularly 3 to 80 hydrogen atoms, and silicon atoms at both ends of the molecular chain are bonded. Organohydrogenpolysiloxane having two (only) hydrogen atoms can be mixed and used in a mass ratio of about 100: 0 to 5:95, particularly about 100: 0 to 8:92. It is preferable from the viewpoint that a flexible (high needle-insertion) silicone gel cured product having good curability can be stably obtained.

The amount of the component (B) added is an alkenyl group in the entire composition (particularly, an alkenyl group in the above-mentioned component (A) and (D), particularly an alkenyl group bonded to a silicon atom in the above-mentioned component (A)). ) The amount of hydrogen atoms bonded to the silicon atom in the component (B) is 0.01 to 3, preferably 0.05 to 2, more preferably 0.2 to 1.5, per one. Is. If the number of hydrogen atoms bonded to the silicon atom of the component (B) is less than 0.01 with respect to one alkenyl group in the entire composition, a cured product cannot be obtained. Further, when the number is more than 3, the heat resistance of the obtained cured product is lowered.

[(C) Platinum-based catalyst]
The component (C) of the present invention serves as a catalyst (hydrosilylation catalyst) for accelerating the addition reaction between the silicon atom-bonded alkenyl group in the component (A) and the silicon atom-bonded hydrogen atom in the component (B). It is what is used. The component (C) is a platinum-based catalyst (platinum or platinum-based compound), and known ones can be used. Specific examples thereof include alcohol-modified products such as platinum black, chloroplatinic acid, and chloroplatinic acid; and complexes of chloroplatinic acid with olefins, aldehydes, vinylsiloxanes, acetylene alcohols, and the like.

The blending amount of the component (C) may be an effective amount and may be appropriately increased or decreased depending on the desired curing rate, but it is usually converted into the mass of platinum atoms with respect to the total mass of the components (A) and (B). It is in the range of 0.1 to 1,000 ppm, preferably 1 to 300 ppm. If this amount is too large, the heat resistance of the obtained cured product may decrease.

[(D) Ketenesilyl acetal type compound, its partially hydrolyzed condensate]
The component (D) of the present invention is one or more of ketensilyl acetal type compounds containing 2 or 3 alkoxysilyl groups in the molecule, which are represented by the following general formula (3) or (4). , And / or a partially hydrolyzed condensate thereof (that is, a ketensilyl acetal type compound having a residual alkoxysilyl group formed by partially hydrolyzing and condensing an alkoxysilyl group), and is a self-adhesive silicone of the present invention. It is an essential component for imparting excellent adhesiveness to the gel composition.
(R ³ O) ₂ Si (R ⁴ ) OC (OR ⁵ ) = CHCH ₃ (3)
(R ³ O) ₃ SiOC (OR ⁵ ) = CHCH ₃ (4)
(In the formula, R ³ and R ⁴ are alkyl groups having 1 to 4 carbon atoms, R ⁵ is an alkyl group having 1 to 12 carbon atoms, and even if R ³ , R ⁴ and R ⁵ are the same as each other. It may be a heterogeneous group.)

In the above general formulas (3) and (4), ^{the alkyl group having 1 to 4 carbon atoms of R 3} and R ⁴ may be linear, cyclic or branched, and may be, for example, a methyl group or an ethyl group. Examples thereof include a propyl group, an n-butyl group, an isopropyl group, a tert-butyl group, a sec-butyl group and an isobutyl group. The ^{monovalent hydrocarbon group having 1 to 12 carbon atoms of R 5} may be linear, cyclic or branched, and may be, for example, a methyl group, an ethyl group, a propyl group, an n-butyl group or a hexyl group. , Heptyl group, octyl group, nonyl group, decyl group and other linear alkyl groups, cyclohexyl group and other cyclic alkyl groups, tert-butyl group, 2-ethylhexyl group and other branched alkyl groups, and these. Examples thereof include a chloromethyl group in which a part or all of the hydrogen atom of the group is substituted with a halogen atom such as chlorine, fluorine and bromine, a halogen-substituted monovalent hydrocarbon group such as a bromoethyl group and a trifluoropropyl group, and the like. These groups may be the same or different. In the present invention, R ³ is preferably a methyl group or an ethyl group, and more preferably a methyl group. R ⁴ is preferably a methyl group, an ethyl group, a propyl group, an n-butyl group or an isopropyl group, and more preferably a methyl group. Further, R ⁵ is preferably a methyl group, an ethyl group, an n-butyl group or a 2-ethylhexyl group, and more preferably a 2-ethylhexyl group.

As the component (D), one type can be used alone or two or more types can be used in combination.

One or more of the above alkoxysilyl group-containing ketenesilyl acetal type compounds, and / or a partially hydrolyzed condensate thereof, are 0.01 to 10 parts by mass with respect to 100 parts by mass of the organopolysiloxane of the component (A). , Preferably used in the range of 0.05 to 5 parts by mass. When the amount of the ketene silyl acetal type compound (D) and / or its partially hydrolyzed condensate added is less than 0.01 parts by mass, the obtained silicone gel cured product has the expected adhesiveness to the substrate. Cannot be expressed. Further, when the addition amount of the ketene silyl acetal type compound of the component (D) and / or its partially hydrolyzed condensate exceeds 10 parts by mass, the flexibility of the obtained silicone gel cured product is impaired or the mechanical properties are deteriorated. It drops.

[Other optional ingredients]
In addition to the above components (A) to (D), any component can be added to the self-adhesive silicone gel composition of the present invention as long as the object of the present invention is not impaired. Examples of the optional component include a reaction inhibitor, an inorganic filler, an organopolysiloxane containing no silicon atom-bonded hydrogen atom and a silicon atom-bonded alkenyl group, a heat resistance imparting agent, a flame retardant imparting agent, and a thixo property imparting agent. Examples include pigments and dyes.

The reaction inhibitor is a component for suppressing the reaction of the self-adhesive silicone gel composition, and specifically, for example, acetylene-based, amine-based, carboxylic acid ester-based, phosphite ester-based, and the like. Reaction inhibitors can be mentioned.

Examples of the inorganic filler include fumed silica, crystalline silica, precipitated silica, hollow filler, silsesquioxane, fumed titanium dioxide, magnesium oxide, zinc oxide, iron oxide, aluminum hydroxide, magnesium carbonate, and calcium carbonate. , Zinc oxide, layered mica, carbon black, diatomaceous earth, glass fiber and other inorganic fillers; these fillers are made of organic silicon compounds such as organoalkoxysilane compounds, organochlorosilane compounds, organosilazane compounds and low molecular weight siloxane compounds. Examples thereof include fillers that have been surface-hydrophobicized. Further, silicone rubber powder, silicone resin powder and the like may be blended.

Typical examples of the organopolysiloxane containing no silicon atom-bonded hydrogen atom and silicon atom-bonded alkenyl group include an organopolysiloxane whose terminal is sealed with an alkyl group such as a methyl group, an ethyl group, or a propyl group. Further, an organopolysiloxane having a terminal modified with an epoxy group, a carbinol group, an aralkyl group, a silanol group, a polyether group, a carboxyl group, a phenol group or the like may be used.

[Curing of self-adhesive silicone gel composition]
The self-adhesive silicone gel composition of the present invention is obtained by mixing the above components (A) to (D) (including any components when any components are blended) according to a conventional method to obtain one liquid. It can be prepared as a mold composition. Further, when preparing the self-adhesive silicone gel composition of the present invention, the components to be mixed are divided into two parts or more as necessary and mixed to form a so-called two-component (or more) type. It may be prepared as a composition, and is divided into, for example, a part composed of a part of the component (A) and a component (C), and a part composed of the rest of the component (A) and the components (B) and (D). It is also possible to mix. When the uncured composition is stored at room temperature as a two-component (or more) type composition, the environment in which the component (A) and the component (B) do not coexist in the presence of the component (C), that is, the component (A) And a part consisting of (C) and (D) components, a part consisting of the rest of (A) component and (B) component, or a part consisting of a part of (A) component and (C) component, It is more preferable to divide it into the rest of the component (A) and the part composed of the components (B) and (D).

Then, the self-adhesive silicone gel composition of the present invention is subjected to 10 to 10 at room temperature (25 ° C. ± 10 ° C.) or under heating temperature conditions according to the application (for example, 35 to 150 ° C., particularly about 50 to 130 ° C.). A cured silicone gel can be obtained by curing for 120 minutes, particularly about 30 to 60 minutes.

In the self-adhesive silicone gel composition of the present invention, the obtained cured product exhibits good adhesiveness to a base material such as a metal such as copper and aluminum and an inorganic substance such as ceramic. It is preferably used for sealing or filling parts.

The cured product (self-adhesive silicone gel or silicone gel cured product) of the self-adhesive silicone gel composition of the present invention preferably has a needle insertion degree of 10 to 100 with a 1/4 cone defined by JIS K2220. , More preferably 15 to 90, still more preferably 20 to 80. When the degree of needle insertion is less than 10, the self-adhesive silicone gel composition cannot withstand the stress when it is cured, and a part of the electronic circuit is broken or cracks are generated inside the cured silicone gel composition. There is. Further, if the degree of needle insertion exceeds 100, the silicone gel cured product is too soft and may be easily peeled off or the adhesiveness to the base material may be lowered when the silicone gel cured product is greatly deformed.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the following Examples do not limit the present invention in any way. In the examples, "parts" represents "parts by mass", "%" represents "% by mass", and "Vi" represents "vinyl group". The needle insertion degree is the needle insertion degree with a 1/4 cone defined by JIS K2220, and was measured using an automatic needle insertion degree meter RPM-101 manufactured by Rigosha.

で示され、２５℃での粘度が１，０００ｍＰａ・ｓの両末端ジメチルビニルシロキシ基封鎖ジメチルシロキサン・ジフェニルシロキサン共重合体を６０部、及び下記平均分子式（６）

で示され、２５℃での粘度が７００ｍＰａ・ｓのトリメチルシロキシ基・ビニルジメチルシロキシ基封鎖ジメチルシロキサン・ジフェニルシロキサン共重合体を４０部、（Ｂ）成分である下記平均分子式（７）

で示され、２５℃での粘度が１００ｍＰａ・ｓの両末端トリメチルシロキシ基封鎖ジメチルシロキサン・メチルハイドロジェンシロキサン共重合体を０．５５部、及び下記平均分子式（８）

で示され、２５℃での粘度が１８ｍＰａ・ｓの両末端ジメチルハイドロジェンシロキシ基封鎖ジメチルポリシロキサンを５．６部、及び（Ｃ）成分である白金原子を１％含有する塩化白金酸ビニルシロキサン錯体のジメチルポリシロキサン溶液を０．０５部、任意成分であるエチニルシクロヘキサノールを０．０２部、及び（Ｄ）成分として、一般式（３）において、Ｒ³、Ｒ⁴＝メチル基、Ｒ⁵＝２−エチルヘキシル基であるケテンシリルアセタール型化合物を０．２４部均一に混合した組成物１を得た（このとき、組成物全体中のアルケニル基１個あたりの（Ｂ）成分中のケイ素原子結合水素原子の個数（以下、Ｈ／Ｖｉという）は１．１９であった。）。得られた組成物１を８０℃で６０分間加熱硬化したところ、針入度４５のシリコーンゲル硬化物を得た。 [Example 1]
(A) The following average molecular formula (5) which is a component

60 parts of both-terminal dimethylvinylsiloxy group-blocking dimethylsiloxane / diphenylsiloxane copolymer having a viscosity at 25 ° C. of 1,000 mPa · s, and the following average molecular formula (6).

40 parts of a trimethylsiloxy group / vinyldimethylsiloxy group-blocking dimethylsiloxane / diphenylsiloxane copolymer having a viscosity of 700 mPa · s at 25 ° C., and the following average molecular formula (7) as a component (B).

0.55 parts of both-terminal trimethylsiloxy group-blocked dimethylsiloxane / methylhydrogensiloxane copolymer having a viscosity at 25 ° C. of 100 mPa · s, and the following average molecular formula (8).

5.6 parts of both-terminal dimethylhydrogensyloxy group-blocking dimethylpolysiloxane having a viscosity at 25 ° C. of 18 mPa · s, and vinyl chloride sulfonate vinylchloride containing 1% of the platinum atom which is the component (C). ^{In the general formula (3), R 3} , R ⁴ = methyl group, R ⁵ with 0.05 part of the dimethylpolysiloxane solution of the complex, 0.02 part of the optional component ethynylcyclohexanol, and the component (D). = A composition 1 in which 0.24 parts of a ketenesilylacetal-type compound as a 2-ethylhexyl group was uniformly mixed was obtained (at this time, a silicon atom in the component (B) per alkenyl group in the entire composition). The number of bonded hydrogen atoms (hereinafter referred to as H / Vi) was 1.19). The obtained composition 1 was heat-cured at 80 ° C. for 60 minutes to obtain a cured silicone gel having a needle insertion degree of 45.

[Example 2]
In Example 1, ^{instead of using 0.24 parts of the ketene silyl acetal type compound having R 3} , R ⁴ = methyl group and R ⁵ = 2-ethylhexyl group in the general formula (3), in the general formula (4). , R ³ = methyl group, R ⁵ = ethyl group, and 0.12 parts of a ketene silyl acetal type compound was used in the same manner to obtain Composition 2. When this composition 2 was heat-cured at 80 ° C. for 60 minutes, a silicone gel cured product having a needle insertion degree of 43 was obtained.

[Example 3]
In Example 1, ^{instead of using 0.24 parts of the ketene silyl acetal type compound having R 3} , R ⁴ = methyl group and R ⁵ = 2-ethylhexyl group in the general formula (3), in the general formula (3). , R ³ , R ⁴ = methyl group, R ⁵ = 2-ethylhexyl group, and 0.24 parts of a partially hydrolyzed condensate of the ketene silyl acetal type compound was used in the same manner to obtain composition 3. When this composition 3 was heat-cured at 80 ° C. for 60 minutes, a silicone gel cured product having a needle insertion degree of 40 was obtained.

[Comparative Example 1]
In Example 1, the composition 4 was obtained in the same manner except that the ketene silyl acetal type compound having ^{R 3} , R ⁴ = methyl group and R ⁵ = 2-ethylhexyl group was not used in the general formula (3). .. When this composition 4 was heat-cured at 80 ° C. for 60 minutes, a silicone gel cured product having a needle insertion degree of 45 was obtained.

[Comparative Example 2]
In Example 1, in the general formula ^{(3), R 3, R} 4 = methyl, the R ⁵ = 2-ketene silyl acetal-type compound is ethylhexyl group instead of using 0.24 parts of 2-ethylhexyl acrylate Composition 5 was obtained in the same manner except that 0.24 part was added. When this composition 5 was heat-cured at 80 ° C. for 60 minutes, a silicone gel cured product having a needle insertion degree of 44 was obtained.

[Comparative Example 3]
In Example 1, in the general formula (3), instead of using 0.24 parts of a ketene silyl acetal type compound having ^{R 3} , R ⁴ = methyl group and R ^{5 = 2-ethylhexyl group, dimethoxymethylsilane was used as 0.} Composition 6 was obtained in the same manner except that 24 parts were added. When this composition 6 was heat-cured at 80 ° C. for 60 minutes, a silicone gel cured product having a needle insertion degree of 68 was obtained.

[Comparative Example 4]
In Example 2, in the general formula (4), instead of using 0.12 parts of the ketenesilyl acetal type compound having ^{R 3} = methyl group and R ^{5 = ethyl group, 0.12 parts of ethyl acrylate is added.} Obtained composition 7 in the same manner. When this composition 7 was heat-cured at 80 ° C. for 60 minutes, a silicone gel cured product having a needle insertion degree of 46 was obtained.

[Comparative Example 5]
In Example 2, in the general formula (4), instead of using 0.12 parts of the ketenesilyl acetal type compound having ^{R 3} = methyl group and R ^{5 = ethyl group, 0.12 parts of trimethoxysilane is added.} Obtained composition 8 in the same manner. When this composition 8 was heat-cured at 80 ° C. for 60 minutes, a silicone gel cured product having a needle insertion degree of 64 was obtained.

[test]
The following tests were carried out using the compositions obtained in Examples 1 to 3 and Comparative Examples 1 to 5. These results are shown in Table 1.

Evaluation of adhesiveness;
A sheared adhesive test piece with an adhesive area of 2.5 mm ² and an adhesive thickness of 2 mm can be produced using various adherends (oxygen-free copper, aluminum, ceramic ( Al ₂ O _{3)) with a width of 25 mm and a length of 100 mm.} The composition obtained as described above was poured and heated at 80 ° C. for 60 minutes to cure. After that, the measurement was carried out by a method according to JIS K6249 to confirm the shear adhesive force and the cohesive fracture rate, and the pass value of the cohesive fracture rate was set to 80%.

Evaluation of storage stability accelerated test;
The compositions of Examples and Comparative Examples were made into two components, and the uncured liquid was left in an environment of 40 ° C. for 1 month, and then both were mixed and mixed so as to have the same mixing ratio as in Examples, and then at 80 ° C. It was heat-cured for 60 minutes, and the degree of needle insertion and adhesiveness were evaluated. When the two components were formed, they were divided as follows and stored in a container capable of blocking moisture.
(1st component) (A) component and (C) component (2nd component) (B) component, (D) component and optional component

[Evaluation]
It can be seen that the compositions of Examples 1 to 3 satisfy the requirements of the present invention and have good adhesiveness to oxygen-free copper, aluminum (metals), and ceramics (inorganic substances). .. Moreover, when the components were divided and the storage stability was evaluated, it was confirmed that there was no change in the degree of needle insertion and the adhesiveness.
On the other hand, since the composition of Comparative Example 1 does not contain the component (D) of the present invention, it can be seen that the adhesiveness to various adherends is poor. Further, since the compositions of Comparative Examples 2 to 5 do not contain the ketene silyl acetal type compound and its partially hydrolyzed condensate, which is the condition of the component (D) of the present invention, the adhesiveness to various adherends is poor. .. From this, the effectiveness of the present invention can be confirmed.

The cured silicone gel (self-adhesive silicone gel) obtained by curing the self-adhesive silicone gel composition of the present invention is any substrate (metals such as copper and aluminum, ceramics, etc.) used for electronic substrates. Since it adheres well to various inorganic substances, it is possible to manufacture electronic parts with improved long-term reliability. From the above, it is expected that reliability will be improved in the future for protection of electronic components such as ICs and hybrid ICs.

Claims (2)

(A) The following average composition formula (1)
R _a R ¹ _b SiO _{(4-ab) / 2} (1)
(In the formula, R is an alkenyl group independently, R ¹ is an unsubstituted or substituted monovalent hydrocarbon group independently containing no aliphatic unsaturated bond, and a is a positive of 0.0001 to 0.2. It is a number, b is a positive number of 1.7 to 2.2, where a + b is 1.9 to 2.4.)
Organopolysiloxane having at least one alkenyl group bonded to a silicon atom in one molecule on average, represented by: 100 parts by mass,
(B) The following average composition formula (2)
R ² _c H _d SiO _{(4-cd) / 2} (2)
(In the formula, R ² is an unsubstituted or substituted monovalent hydrocarbon group independently containing no aliphatic unsaturated bond, c is a positive number of 0.7 to 2.2, and d is 0.001. It is a positive number of ~ 1.0, where c + d is 0.8 ~ 3.0.)
Organohydrogenpolysiloxane having at least two hydrogen atoms bonded to silicon atoms in one molecule represented by: Hydrogen atom bonded to silicon atom in component (B) per alkenyl group in the entire composition Amount of 0.01 to 3 pieces,
(C) Platinum-based catalyst: an effective amount, and (D) one or more of the alkoxysilyl group-containing ketenylsilyl acetal type compounds represented by the following general formula (3) or (4), and / or the alkoxysilyl. Alkoxysilyl group of group-containing ketensilyl acetal type compound Ketensilyl acetal type compound having residual alkoxysilyl group formed by partially hydrolyzing and condensing : 0.01 to 10 parts by mass (R ³ O) ₂ Si ( R ⁴ ) OC (OR ⁵ ) = CHCH ₃ (3)
(R ³ O) ₃ SiOC (OR ⁵ ) = CHCH ₃ (4)
(In the formula, R ³ and R ⁴ are alkyl groups having 1 to 4 carbon atoms, R ⁵ is an alkyl group having 1 to 12 carbon atoms, and even if R ³ , R ⁴ and R ⁵ are the same as each other. It may be a heterogeneous group.)
A self-adhesive silicone gel composition containing. A self-adhesive silicone gel comprising a cured product of the self-adhesive silicone gel composition according to claim 1.